Predicting why, how, and when mine tailings disposal sites become prone to dust scattering events is often hampered by our limited understanding of the factors that affect the drying rates from their surface layers. As a case study, thermal imaging is demonstrated here to be a valuable tool to study the evaporation mechanisms and rates from bauxite residues as a function of their thickness and physicochemical properties, as well as environmental conditions. These investigations reveal that their late stage drying rates are limited by gas phase diffusion through the interstitial air within their internal microporosity. The smallness of the effective diffusion coefficient indicates that water adsorption on bauxite residues surfaces is the dominant phenomenon responsible for their slow water vapour transport kinetics, a phenomenon that ultimately controls their late stage drying rates, that is when dust scattering is most likely to occur. As such, application of this thermal imaging methodology in the field may also contribute to improve the accuracy of risk assessment protocols, support intervention and mitigation strategies, underpin optimization efforts for mining residues management, and improve forecasting of fugitive dust emissions from mine tailings by enabling more accurate predictions of the evolution in their surface drying state.

中文翻译：

---

热成像方法研究矿山尾矿中的蒸发动力学

由于我们对影响其表层干燥速率的因素的了解有限，因此常常难以预测为什么，如何以及何时使矿山尾矿处置场容易发生粉尘飞散事件。作为一个案例研究，这里证明了热成像是研究铝土矿残留物的蒸发机理和速率的函数，这些蒸发器和速率是其厚度和理化性质以及环境条件的函数。这些研究表明，它们的后期干燥速率受到内部微孔内间隙空气中气相扩散的限制。有效扩散系数较小表明铝土矿渣表面上的水吸附是导致其缓慢的水蒸气传输动力学的主要现象，最终控制其后期干燥速度的现象，即最有可能发生灰尘飞散的现象。因此，该热成像方法在现场的应用还可能有助于提高风险评估协议的准确性，支持干预和缓解策略，支持采矿残余物管理的优化工作，以及通过实现对矿山尾矿产生的扬尘排放的预测更准确地预测其表面干燥状态的演变。